I started reviewing this one. Here are my initial findings:
! The specfile in th link above does not match the specfile that comes inside the SRPM. I started the review with the latter.
* Missing BR: lv2core-devel sord-devel (You BR sord instead, which is insufficient). I suggest using mock which will tell you the BRs you need to add.
* The directory /etc/bash_completion.d/ remains unowned. We can either own this directory, or add Requires: bash_completion. But looking at the multiple owners of the directory /etc/bash_completion.d/ I can say that we should also own this directory.
* You can pass "--bindings" to "./waf configure" to build the Python bindings. Note that you will then also need BR: swig python-devel (Just BR: python is not sufficient)
* Fedora specific compilation flags are not honored. You will need to export CFLAGS instead, as the source is written in C.
! Since you build the unit test via --test, you should probably run the test in %check.
* %{_mandir}/man1/* should go into the main package, as these are manpages for stuff that goes to /usr/bin.
* License tag should be MIT.
! Buildroot tag is no longer required. Does no harm though.

Thank you for the update. Here is the rest of the review:
* Missing BR: swig
! BR: python is redundant. Does no harm though.
* BR: boost-devel and glib2-devel are redundant. It would be good to remove them so that we don't have to drag in unrelated packages during a build.
? Could you backport the fixes from the trunk and run the tests?
* I am not sure we need to divide the Python modules in two subpackages. At the very least the noarch package should require the arch specific one, since lilv.py has
import _lilv
referring to _lilv.so. Can _lilv.so be used without lilv.py? If not, they should probably go to the same package (feel free to disagree :)).
- rpmlint says:
lilv.x86_64: W: non-conffile-in-etc /etc/bash_completion.d/lilv
lilv.x86_64: W: no-manual-page-for-binary lilv-bench
python-lilv.noarch: W: no-documentation
These can be ignored.
* /usr/share/man/man3/* should go to the devel package as this is development documentation.

Package lilv-0.5.0-3.fc17:
* should fix your issue,
* was pushed to the Fedora 17 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing lilv-0.5.0-3.fc17'
as soon as you are able to.
Please go to the following url:
https://admin.fedoraproject.org/updates/FEDORA-2012-3143/lilv-0.5.0-3.fc17
then log in and leave karma (feedback).